The present invention relates generally to a folding toolbar and more specifically to a hydraulic sequence control for folding the outrigger frames on a toolbar.
As tractors are made larger and farms increase in size, farm implements are widened to cover a larger swath during each pass through the field. Transporting implements continues to be a source of difficulty since the transport width must be sufficiently narrow to pass through gates and over bridges and public roads and the like. Folding toolbars have been devised with a main frame having a pair of outrigger frames hinged to its ends for folding upwardly about a horizontal pivot to a narrow transport position. When the outrigger frames have a combined width less than the width of the main frame, they can be folded together approximately 180.degree. to a position directly over the main frame. However, a problem exists when it is desirable to have an implement transport width less than half the field work width, since both outriggers cannot fold 180.degree. without interference from each other. Commonly each of the outriggers is folded slightly more than 90.degree. so that it projects upwardly and just inside the main frame. This arrangement does not provide as compact and stable transport configuration as one with outriggers which fold approximately 180.degree..
Heretofore it was not practical to add extensions to the 180.degree. fold outrigger frames, for example to increase row crop cultivator width from 16 to 18 rows, because the extensions would interfere with each other when the outriggers were folded between the transport and field-working positions. To add outrigger extensions to an existing 180.degree. wing fold arrangement would require a new or extensively revised hydraulic folding system.
When turning in the headlands with a tractor mounted wingfold toolbar, it is often desirable to activate the hydraulic folding system and lift to outriggers approximately 5.degree. to prevent the outer ends of the implement from contacting the ground during the turn. Previously available hydraulic systems for raising the outriggers included specially designed dual function cylinders for operating in one mode during turns and in another mode during folding and unfolding of the outriggers between the transport and field-working positions. These cylinders are more complex and expensive than other types of cylinders utilized for folding and unfolding the outriggers.
It is therefore an object of the present invention to provide an improved hydraulic folding system for wing-fold implements.
It is another object of the invention to provide a relatively inexpensive and simple folding sequence control for wing-fold implements.
It is yet another object to provide an improved hydraulic system for folding a wing-fold implement to less than half its field-working width while providing a relatively low, stable transport configuration.
It is a further object to provide a simple and yet reliable control for raising the outriggers of a folding toolbar together during the first portion of the fold cycle and thereafter sequencing the folding to provide the desired movement of the outriggers to and from the transport position so they do not interfere with each other. It is also an object to provide such a control which does not require special hydraulic cylinders or more than one hydraulic outlet.
It is a further object of the invention to provide a control which can be added to an existing 180.degree. folding toolbar to permit the outriggers to be extended to a total combined width greater than the width of the main frame while preventing interference between the outriggers during folding and unfolding, and while causing the outriggers to fold in unison for the first part of the fold cycle.
The first outrigger of a 180.degree. folding toolbar is folded to a 180.degree. position first after which the second outrigger is folded to about a 150.degree. position where it is supported just above the end of the first outrigger. Restrictors are added in series to the hydraulic line for the second outrigger cylinder. A one-way plunger operated ball check valve bypasses the restrictors for the first 5.degree. of fold. The check valve is located on the main frame in the hinge area and is operated by an arm on the outrigger. In the field-working position of the toolbar, the plunger is depressed so that when hydraulic pressure is applied to the cylinders the outriggers raise together for the first 5.degree.. At this point, the plunger closes the check valve to slow the folding of the second outrigger. During unfolding the check valve allows the hydraulic fluid to bypass the restrictors so the first and second outriggers unfold at the same speed, thus insuring that the second outrigger will be out of the way of the first outrigger. This arrangement permits the total width of the outriggers to be greater than the width of the main frame, and provides a simple and yet reliable means for raising the outriggers together during the first portion of the fold cycle.
These and other objects, features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description taken with the accompanying drawings.